Marijuana Law, Policy & Reform

Editor: Douglas A. Berman
Moritz College of Law

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Tuesday, February 18, 2014

Could marijuana reforms end up making our roadways much safer?

The question in the title of this post might be a bit of foolish wishful thinking on my part, but these passages from this notable new New York Times article provides the foundation for my (undue?) optimism:

[S]cience’s answers to crucial questions about driving while stoned — how dangerous it is, how to test for impairment, and how the risks compare to driving drunk — have been slow to reach the general public.  “Our goal is to put out the science and have it used for evidence-based drug policy,” said Marilyn A. Huestis, a senior investigator at the National Institute on Drug Abuse.  “But I think it’s a mishmash.”

A 2007 study found that 12 percent of the drivers randomly stopped on American highways on Friday and Saturday nights had been drinking.  (In return for taking part in the study, intoxicated drivers were told they would not be arrested, just taken home.)  Six percent of the drivers tested positive for marijuana — a number that is likely to go up with increased availability.  Some experts and officials are concerned that the campaign against drunken driving has not gotten through to marijuana smokers.

“We’ve done phone surveys, and we’re hearing that a lot of people think D.U.I. laws don’t apply to marijuana,” said Glenn Davis, highway safety manager at the Department of Transportation in Colorado, where recreational marijuana use became legal on Jan. 1. “And there’s always somebody who says, ‘I drive better while high.’ ”

Evidence suggests that is not the case. But it also suggests that we may not have as much to fear from stoned driving as from drunken driving.  Some researchers say that limited resources are better applied to continuing to reduce drunken driving.  Stoned driving, they say, is simply less dangerous.

Still, it is clear that marijuana use causes deficits that affect driving ability, Dr. Huestis said.  She noted that several researchers, working independently of one another, have come up with the same estimate: a twofold increase in the risk of an accident if there is any measurable amount of THC in the bloodstream....

The estimate is low, however, compared with the dangers of drunken driving. A recent study of federal crash data found that 20-year-old drivers with a blood-alcohol content of 0.08 percent — the legal limit for driving — had an almost 20-fold increase in the risk of a fatal accident compared with sober drivers. For older adults, up to age 34, the increase was ninefold.

The study’s lead author, Eduardo Romano, a senior research scientist at the Pacific Institute for Research and Evaluation, said that once he adjusted for demographics and the presence of alcohol, marijuana did not statistically increase the risk of a crash. “Despite our results, I still think that marijuana contributes to crash risk,” he said, “only that its contribution is not as important as it was expected.”

The difference in risk between marijuana and alcohol can probably be explained by two things, Dr. Huestis and Dr. Romano both say. First, stoned drivers drive differently from drunken ones, and they have different deficits. Drunken drivers tend to drive faster than normal and to overestimate their skills, studies have shown; the opposite is true for stoned drivers. “The joke with that is Cheech and Chong being arrested for doing 20 on the freeway,” said Mark A. R. Kleiman, a professor of public policy at the U.C.L.A. School of Public Affairs....

Another factor is location. A lot of drinking is done in bars and clubs, away from home, with patrons driving to get there and then leaving by car. By contrast, marijuana smokers tend to get high at home....

All of these facts lead experts like Dr. Romano and Dr. Kleiman to believe that public resources are better spent combating drunken driving. Stoned driving, they say, is best dealt with by discouraging people from mixing marijuana and alcohol — a combination that is even riskier than alcohol alone — and by policies that minimize marijuana’s risk on the road.

For instance, states that legalize recreational marijuana, Dr. Kleiman said, should ban establishments like pot bars that encourage people to smoke away from home. And Dr. Romano said that lowering the legal blood-alcohol concentration, or B.A.C., to 0.05 or even 0.02 percent would reduce risk far more effectively than any effort to curb stoned driving. “I’m not saying marijuana is safe,” he said. “But to me it’s clear that lowering the B.A.C. should be our top priority. That policy would save more lives.”

My supposition based on this article that marijuana reforms could end up making our roadways much safer is a result of two potential impacts of ending pot prohibition: (1) if marijuana reform leads a number of people who would generally go get drunk at a bar to instead now just get stoned at home, the net effect will be safer roads, and (2) if enduring concerns about the impact of marijuana reform leads more policy-makers to focus on highway harms, we might see a greater effort to get much tougher on the enduring public safety disaster that is drinking and driving.

I am not expecting that we will get strong evidence that marijuana reforms end up making our roadways much safer anytime soon, but I am hopeful that researchers like Dr. Romano and Dr. Kleiman continue to stress that our modern alcohol policies and practices now impact highway safety much more than any marijuana reforms are likely to do. And, as these related recent articles also highlight, the media so far is doing a pretty good job defusing the risk of misguided reefer madness when it comes to driving under the influence:

http://lawprofessors.typepad.com/marijuana_law/2014/02/could-marijuana-reforms-end-up-making-our-roadways-much-safer.html

Criminal justice developments and reforms, Recreational Marijuana Commentary and Debate, Recreational Marijuana State Laws and Reforms | Permalink

Comments

I know you are bending over backwards to not endorse stoned driving (i don't either) but you dance around the conclusion you clearly put forward. Any substitution of drunk driving by stoned driving will make the roads safer by a factor of 10. The plain fact is that drunk drivers are way more dangerous than stoned ones.

Posted by: mitch | Feb 21, 2014 12:54:47 PM

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